Some gameplay details have come to light about Spike's Jawa: The Mammoth and the Mysterious Stone, which do a lot to continue the Tail of the Sun comparison. Of course, the simplistic (but different) graphical style and the caveman theme go a long way in that direction, as well. But the game veers from Tail of the Sun in a few ways.
Like Tail of the Sun, the game centers around the survival of a small tribe of cavemen. Hunting and gathering food is important, and as you get stronger, you can expand your search area without succumbing to fatigue. However, Jawa takes more of an action-adventure game approach, putting you in control of one character and allowing you to ride animals to traverse the area. Battles use a rhythm-based Wiimote-shaking method.
This game has more of an emphasis on communication and (asynchronous) multiplayer, as well. Up to four players can occupy the same settlement and send each other messages. It's just like Animal Crossing, except you hunt and eat all the animals!